Process of treating printing-plates.



No. 872,630. PATPNTPD DPC. 3, 19o?.

- M. A. MOKEB. PROCESS OP TREATING PRINTING PLATES.

APPLICATION FILED AUG. 30! 1904. RENEWBD HAY 20, 1907.

r.s n-"A f3 fl'flED STATES PEQT @.Flfltj.

MILTON A. MCKEE, OF NEW YORK, N. Y., ASSGNOR TO C. B. COTTRELL t SONS COMPANY, OF

' NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS 0F TRETNG PRNTNG-LATES.

Patentes nee. e, ree?.

Application filed August 30.1904. Serial No. 222.713. Renewed MayZO. 1907. Serial No. 374.726.

To all 'whom it may concern:

Be it known that I, MILTON A. MGKEE, a

citizen of the United States, and resident of theborough of Manhattan, in the city and State of NewA York, have invented a new and useful Improvement in the Process of Treating Printing-Plates, of which the following is a specification.

This present invention consists in the process of treating the faces of electrotype or stereotype printing plates for the purpose of correcting or preventing a hard printing im ression on the edges of the lates.

n t e useof printing plates it ias been found that as the impression cylinder rolls u on to the e ge of the p ate is impressed into the surface of the cylinder for the reason that the plate su port and bed are unyielding while the su ace of the impression cylinder is more or less yielding because it is packed with a series of sheets of paper. he opposite edge of the plate also produces an indentation in the cylinder as the cylinder leaves the plate. This serves to produce a hardirnprint along the edges of the plate and also indents the sheet being printed sulliciently to emboss it at thosev points. The method now in practice for obviating this difliculty is to tear out the make ready sheets which constitute the packing on the impression cylinder. This :method is not satlsfactory for the reason that the impression surface of the cylinder should not, be lowered for the edges of the plates but should remain at a unifornrlevcl. 'lo produce the best results the edges of the plate should be lowered.

My invention consists in the process hereinafter described of treating the plates so as to depress their printing faces along the edges thereof. y

I The procedure is as follows: An impression of the plates which are to constitute the printing form is pulled. Several strips ol' French folio paper are then cut. A strip of this paper is pasted on cach side edge of the prootA so as to overlap the impression of the reading matter a short distance as, for instance about one sixteenth of an ineh.- Another strip of paper is then pasted on the top of the previously pasted strip so as to lap over the reading matter a short distance beyond the first named strip as, for instance, from one sixteenth to one eighth of an inch.

printing surface of a plate, the

Vihis process may be repeated until the face of the proof is raised continuously along its edges to reduce a matrix of the required form, wit l each of its raised portions of the same height throughout its length. The matrix .is then laid upon the bed of a shaving machine. rlhe printing plate is then placed face down upon the vmatrix andregistered therewith` The back of the plate'is then shaved until it is perfectly fiat, this shaving process serving to remove the metal from the back of the plate and where it has been raised by the engagement of the side edges of the face of the plate with the raised portions of the matrix. Thel matrix and plate 'are then removed from the. bed of the v shaving machine. The `matrix is placed upon a sheet of olished brass, preferably about an eighth ol' an inch thick, the face of the matrix' being up. 'lhc plate is then registered face downward on the matrix and the sheet of brass, vmatrix and plate are 'slid' in between the two parallel surfaces of a heating box. 'lhefollow'er of the heating box is screwed downward until it just touches the back of the plate and is allowed to rest there until the brass and printing plate are both thoroughly heated. Pressure is then applied and the plate being in a semisoi't state, takes on the character of the matrix. The pressure is then removed and the brass, matrix and plate are removed' from the heating box and inserted between thel parallel surfaces of a cooling box. Pressure is there applied whileI the plate is beingr allowed to cool.. rlhe plate then ready to he put upon the press.

lt will he found that when the form is 'made up and put upon the bed ol' the press `and the impression surface of the cylinder packed to one uniform thickness, that the iirst impression upon a sheet will be correct and wil not show a heavy .impression or embossing along the edges oll the printed mat ter thereon, thus producing an even im )ression throughout. Furthermore, the liieA of the plate is increased at least fifty per cent.

rlhe invention is illustrated in the accompanying drawings in whichv Figure l represents a plan View of the completed matrix, portions of the side strips which form the raised parts of the matrix being broken awa)v to more clearly show' the method of lapping the strips over the edges ol" the printed matter en the proof, Fig. 2 is a transverse section taken in the plane of the line VA-A of Fig. 1 Fig. 3 is a transverse seetion showing the plate and matrix in a shaving machine, the back of the plate being sub- 5 jected to the shaving operation; Fig. 4 is a transverse section throu h the plate showing the form which it wou d assume when removed lfrom the shaving machine; Fig. 5 is a sectional view of the plate and matrix shown in connection with the flat bed 'and follower the same height throughout its length and is herein shown as composed of three strips of apei, 2, 3 and 4, the strip 2 being pasted 'rectly on to the proof 1 with its inner edge overlapping the printed matter thereon to the desired point. The strip 3 is shown as projecting a short distance further on to the printed matter of the proof l and the strip 4 as projecting still further on to the printed matter.

y The plate is denoted by 5. It is registered with the matrix with the side edges of its printing face in engagement with the raised portions of the matrix. The plate and matrix are placed in a shaving machine between the bed 6 and the knife 7 and run through the said machine.

action of the knife serves to remove the suthe s aving machine.

perfluous metal on the back of the late at its edges, the shavings being herein esignated by 8, until the back of the plate is level. The late and matrix are then removed from The matrix is placed face up upon 'a sheet of brass 9. The plate is registered therewith face downward and the brass sheet, matrix and platcare in Serted between two smooth fiat parallel surfaces 10, 11, suoli, for instance, as the bed and follower of a heating box or press, which are heated to a suitable degree of temperature to soften the metal of the plate so as to cause it to assume the desired forin.- The 50 brass sheet, matrix and plate are, after being subjected to )ressure on the heating box, re-

moved there 'om and placed between two iat parallel surfaces 12, 13, of a cooling box where they are also subjected to pressure.

This will cause the plate to retain itsjform with the edges of its printing face depressed evenly and the plate will then be ready to be. put upon the press read to print.

' It is to be uiiderstoo that this method of treating printing plates may be successfully faces.

used in connection with the process set forth in my United States Letters Patent No. 760,235 dated May 1,7, 1904, for treating uneven printing plates forhevening their sur- When used in connection with the The plowing and pressing recess referred to, the two matrices would both be placed upon the bed of a shaving machine in connection with the plate and the plate, shaved in the usual manner. The plate would then be subjected to the heating and cooling operations without the use of the matrices used for evening the faces of the plate.

Whatl claim as my invention is:

1. The process of treating printing plates for the'purpose of correcting or preventing a hard printing impression on the edges of the plates, which consists in subjecting the plate to pressure while its face is in contact with a matrix having a continuous raised portion of thev saine height throughout its length along each' of the side edges of the plate.

2. The process of treating printing plates for the purpose of correcting or preventiiw a hard printing impression on the edges of the plates, which consists in subjecting the plate to pressure while its face is in contact with a matrixhaving a continuous raised portion of the .saine height throughout its length along each of the side edges of the plate and sub- 'jectirig the plate to pressure and heat between two parallel surfaces while the plate isiii contact with the matrix.

3. The process of treating printing plates for the purpose of correcting or preventine a hard printing impression on the edges of lhe plates, which consists in subjecting the plate to pressure while its face is in contact with a matrix having a continuous raised portion of the saine height throughout its length along each of the side edges of the plate, subjecting the late to pressure and heat between two para el surfaces while the plate is in contact with the' matrix and finally cooling the plate while under pressure.

4. The process'of treating printing plates for the purpose of correcting or preventinir a hard rinting impression ori-the edges of t e plates, which consists in subjecting the plate to a shaving operation while its face is in contact with a matrix having a continuous raised ortion of the same height throughout its elngth alongeach of the side edges of the p ate.

5. The process' of treating'printing plates for the purpose of correcting or preventinfr a hard printing impression on the edges oft e plates, which consists in subjecting the plate to a shaving operation while its face is in contact with a matrix having a continuous raised ortion of the saine `height throughout its ength along cach of the side edges of the plate and subjecting the late to pressure and heat between two parallel surfaces while in contact with the matrix.

6. The. process of treating printing plates for the purpose of correcting or preventing a hard printing impression on the edges of t 1e plates, which consists in subjecting the plate to a shaving operation while its face is in conf afterward subjecting the pla-teend matrix to 20 for the purpose of correcting or preventing a herd printing impression on the edges of the pistes, which consists in 1placing the plete with its ieee in contee-t wit i n matrix having 'e oontinuous raised portion 4oi the seme height throughout its length alon each of the side edges of the Contact, subjecting the plete at the seme time to pressure against the matrix by the act Sharing operation on its V tact withametrix havinge continuous raised portion of the same height througlieut its ength along eeoh of the side edges of the late, subjecting the'plete to pressure end, i

' '5 estA between two parellel surfaces while in l j Contact with the matrix and finally cooling l l t e plate 'while under pressure. i

A. he process of treating printing pistes f foi-'the purpose of correcting or preveA g 1Q .hard prlntin impression on the edg n i the platespwhielgi consists in placing the plete with its face Contact with e matrix having l 's injecting the piste and matrix to pressure end heet between two pereilel surfaoesand finally subjecting the plate toe, Cooling operation While under pressure,

in testimony, that I claim the foregoing as a Continuous raised portion oi" the saine height throughout its length along each of 15 the side edges of the plate, then while in such Contact, subjecting the plete at the seine time to pressure against the matrix by the not of asheving voperation on its beek and niyinvention, I have signed my name in presence oi two witnesses, this ninth day of l August 1904.

g MILTON A. MCKEE.

Witnesses: l FREDK. HAYNES, 1 HENRY THIEME;

pressure and heat between two parallel suraces.

8. The process of treating printing plates plete, then wh' e in such beek, afterward 

